How to restore Default Security Permissions?

Hi quikemolina,
To reset the security settings back to default, take a look at the following KB article:
http://support.microsoft.com/kb/313222
•Click the Start orb.
•Under Start Search, type cmd, and then press enter.
•Type the following command, and then press enter:
 secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose

You will receive a "Task is completed" message, and a warning message that something could not be done. You can safely ignore this message.
Additional information:
http://social.answers.microsoft.com/Forums/en-US/vistasecurity/thread/7eacb966-cbbd-41ac-b08d-7c7f881943be/

If the above steps fail, I would suggest you to perform system restore, the following steps will help you to perform system restore.
1.         Click Start, type system restore in the Start Search box, and then click System Restore in the Programs list.
If you are prompted for an administrator password or confirmation, type your password or click Continue.
2.         In the System Restore dialog box, click Choose a different restore point, and then click next.
3.         In the list of restore points, click a restore point that was created before you began to experience the issue, and then click next.
4.         Click Finish.
Note: When you use System restore to restore the computer to a previous state, programs and updates that you installed are removed.
Refer to this link for step by step procedure to System Restore
http://support.microsoft.com/kb/936212
The computer restarts, and the system files and settings are returned to the state that they were in at the time that the restore point was created.

Hope this helps. Let us know the results.
Thanks & Regards,
Vijay B – Microsoft Support
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